Morphologic techniques are applied to dissociated cell cultures of central nervous system. Tetanus toxin binding, visualized by immunohistochemistry, has proven an effective neuronal label within only a few hours of plating. Radioautography has shown that chronic exposure to benzodiazpine results in an apparent decrease in benzodiazpine receptors. The methodology has been refined for the preparation of multicompartment culture chambers to study the effects of neuronal activity on the formation, elimination, and stabilization of synaptic contacts. Reproducible survival of both input and target neurons is a minimal requirement for such studies. Reliable preparations have been achieved, and preliminary data indicate that chronic electrical stimulation is correlated with a relative increase in the number of stable synaptic contacts. Additional experiments indicate that stimulation confers no particular advantage in terms of neurite outgrowth, and may be somewhat detrimental in terms of neuron survival.